[Gasification] gas composition

[Louis Peltier]

could some one tell me what the gas composition is
when wood is heated in a CLOSED  container to make charcoal.
(no air is allowed in the closed container)
is the gas differant after the wood has turned to charcoal and
you continue to heat the container at even higher temps with no air 
alowed into the closed container.
thanks
Louis in sunny central BC